1. Field of the Invention
The present invention relates to an improvement in a body frame of a motorcycle.
2. Description of Background Art
A mainstream body frame of a motorcycle is composed of left and right main frames formed integrally with a head pipe, whereby an engine is suspended and supported therebetween.
A motorcycle is known which includes left and right main frames wherein part of which can be separated and wherein the engine is suspended and supported therebetween.
A body frame is disclosed in JP-A No. 2004-256005 (FIG. 2) wherein main frames thereof are provided for suspending and supporting the engine and the like.
As illustrated in FIG. 2 of JP-A No. 2004-256005, the frame of a motorcycle is disposed with a front frame 5 and a rear frame 20 being separated from each other. The front frame 5 is mounted on a cylinder block 8 wherein the rear frame 20 is an approximate diamond-shaped frame, as viewed from the side, and is located at the rear of a case 7 constituting an engine 6. Thus, the frame is reduced in size and weight by attaching a rear portion of the case 7 and also a rear swing arm 25 to the frame 20.
According to JP-A No. 2004-256005, if the engine increases in size it is necessary to increase the binding rigidity.
Thus, a technology is desired that enables ensuring a predetermined binding rigidity between the body frame and the engine, while reducing the weight of the body frame including the main frame.